Highly abrasion-resistant polyolefin pipe

ABSTRACT

A pipe- or tube-shaped article having an innermost layer is disclosed which comprises a polyolefin composition comprising a polyolefin comprising ethylene and an α-olefin. The article provides long lifetime, highly abrasion-resistant pipes for mining and other transportation uses. Also disclosed are methods for preparing the article and transporting abrasive materials.

This application claims priority to U.S. provisional application 61/110,424, filed Oct. 31, 2008; the entire disclosure of which is incorporated herein by reference.

The invention relates to highly abrasion-resistant tubular articles comprising polyolefin layers that provide for the transport of particulates and slurries, methods and compositions to produce the articles, and methods of transporting abrasive materials through them.

BACKGROUND OF THE INVENTION

Mining operations require the transport of highly abrasive particulate or slurry streams. The recovery of bitumen from oil sands is becoming increasingly important within the energy industry. Processing oil sand includes transporting and conditioning the oil sand as an aqueous slurry over kilometer lengths of pipe up to 1 meter in diameter. Processes for the recovery of bitumen from oil sands are known (U.S. Pat. Nos. 4,255,433; 4,414,117; 4,512,956; 4,533,459; 5,039,227; 6,007,708; 6,096,192; 6,110,359; 6,277,269; 6,391,190; 2006/0016760; US2006/0249431; US2007/0023323; US2007/0025896; WO2006/060917; CA1251146; CA2195604; CA2227667; CA2420034; CA2445645; and CA2520943). Use of caustic to assist in the recovery process of oil from oil sands is also known (US2006/0016760 and US2006/0249431). Other mining operations that include the transport of highly abrasive particulate or slurry streams from the mine to processing refinery include, for example, iron ore, coal and coal dust, and the like, and in further non-mining transport processes, such as grain, sugar and the like.

Often, metal pipes, such as carbon steel or cast iron pipes, are used for the transport of these highly abrasive streams. They are expensive, heavy and only provide a temporary solution since they are eventually destroyed. To increase their lifetimes, the metal pipes may be rotated 90 degrees on their axes on a regular basis to provide a new transport surface. However, because of the pipe weight, this rotation is difficult and ultimately the entire pipe is worn out and must be replaced.

Use of plastic pipes, pipe liners and pipe coatings has been proposed to reduce these shortcomings. Material selection is critical. Many of the commonly available materials cannot stand up to such highly-abrasive mining streams and are quickly worn out. For example, high density poly(ethylene) pipes are generally used as liners for sanitary sewer and wastewater pipelines but they rapidly degrade under highly abrasive environments. U.S. Pat. No. 4,042,559 discloses abrasive granule-filled, partially-cured coatings for use in abrasion resistant coated pipes for the transport of mining slurries. U.S. Pat. No. 4,254,165 discloses processes to produce abrasion resistant pipes with 0.04-0.05-inch thick coatings of filled (such as sand) polyolefins, such as low and medium density poly(ethylene) and including poly(ethylene-co-acrylic acid). U.S. Pat. No. 4,339,506; WO90/10032 and CA1232553 disclose rubber liners for pipes. U.S. Pat. No. 4,215,178 discloses fluoropolymer-modified rubber pipe liners. US2006/0137757 and US2007/0141285 disclose fluoropolymer pipe liners. Polyurethane pipe coatings are known (U.S. Pat. No. 3,862,921; U.S. Pat. No. 4,025,670; US2005/0194718; US2008/0174110; GB2028461; JP02189379; JP03155937; and JP60197770). US2005/0189028 discloses metal pipe coated with a polyurethane liner to transport tar sand slurry. GB2028461 discloses an abrasion-resistant pipe lining comprising a urethane rubber thermoset embedded with the particles of the material to be transported (coal dust, grain or sugar) through transport of the materials during curing. Abrasion resistant pipes with elastomeric polyurea coatings are disclosed in U.S. Pat. No. 6,737,134. A shortcoming of the polyurethane coatings includes the highly complex processes for applying the coating to the metal pipe.

Use of polyolefin compositions made from polyolefin compositions as pipes, pipe liners and pipe coatings is known. For example, U.S. Pat. No. 4,481,239 discloses polyethylene powder coatings for pipes which may include an adhesive layer comprising certain acid copolymer powder coatings.

U.S. Pat. Nos. 3,932,368, 4,237,037, 4,345,004 and 4,910,046 disclose polyolefin powder coatings for metal substrates which may include polar group modified olefinic resins, such as carboxyl- or anhydride-modified resins. U.S. Pat. No. 5,211,990 disclose a flame spraying process of polyolefin powders onto metal substrates that include polyolefins grafted with acid or anhydride functionality and ethylene/(meth)acrylic acid copolymers and ionomers derived therefrom. U.S. Pat. No. 5,275,848 discloses a powder coating process for metal substrates with polyolefin powders that include polyolefins grafted with acid or anhydride functionality and ethylene/(meth)acrylic acid copolymers and ionomers derived therefrom. U.S. Pat. Nos. 5,677,377 and 5,677,378 disclose corrosion -resistant powder coatings for steel plate which include maleic anhydride-grafted polypropylene powder. U.S. Pat. No. 5,976,652 discloses corrosion-resistant polypropylene film coatings for steel containers adhered with carboxylic acid- or anhydride-functional polypropylenes.

A shortcoming of the art polyolefin pipes, pipe liners and pipe coatings is low abrasion resistance resulting in short service lifetimes.

SUMMARY OF THE INVENTION

The invention is directed to a pipe- or tube-formed article having an innermost layer wherein the innermost layer has a thickness of about 0.001 to about 102 mm and comprises a polyolefin composition, the polyolefin comprising ethylene and an α-olefin having 3 to 20 carbons having a density of about 0.92 g/cc (ASTM D-792) or less.

The invention is also directed to a method for producing a polyolefin-lined metal pipe comprising the step of pulling or inserting a pre-formed polyolefin pipe or multilayer polyolefin pipe into a preformed metal pipe.

The invention also provides a method to produce a polyolefin-lined metal pipe comprising the step of laying up a pre-formed polyolefin film or sheet or multilayer polyolefin film or sheet into a preformed metal pipe.

The invention also provides a method for transporting an abrasive material comprising obtaining a pipe- or tube-formed article as described above; preparing an abrasive material composition suitable for pumping through the article; pumping the abrasive material composition into one end of the pipe- or tube-formed article and receiving the abrasive material composition out of the other end of pipe- or tube-formed article.

DETAILED DESCRIPTION OF THE INVENTION

All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control.

Except where expressly noted, trademarks are in upper case.

Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described herein.

Unless stated otherwise, all percentages, parts, ratios, etc., are by weight. When an amount, concentration, or other value or parameter is given as either a range, preferred range or a list of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. Where a range of numerical values is recited herein, unless otherwise stated, the range is intended to include the endpoints thereof, and all integers and fractions within the range. It is not intended that the scope of the invention be limited to the specific values recited when defining a range.

When the term “about” is used in describing a value or an end-point of a range, the disclosure should be understood to include the specific value or end-point referred to.

As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “containing,” “characterized by,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Further, unless expressly stated to the contrary, “or” refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

The transitional phrase “consisting of” excludes any element, step, or ingredient not specified in the claim, closing the claim to the inclusion of materials other than those recited except for impurities ordinarily associated therewith. When the phrase “consists of” appears in a clause of the body of a claim, rather than immediately following the preamble, it limits only the element set forth in that clause; other elements are not excluded from the claim as a whole.

The transitional phrase “consisting essentially of” limits the scope of a claim to the specified materials or steps and those that do not materially affect the basic and novel characteristic(s) of the claimed invention. “A ‘consisting essentially of’ claim occupies a middle ground between closed claims that are written in a ‘consisting of’ format and fully open claims that are drafted in a ‘comprising’ format.”

Where applicants have defined an invention or a portion thereof with an open-ended term such as “comprising,” it should be readily understood that (unless otherwise stated) the description should be interpreted to also describe such an invention using the terms “consisting essentially of” or “consisting of”

Use of “a” or “an” are employed to describe elements and components of the invention. This is done merely for convenience and to give a general sense of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.

In describing certain polymers it should be understood that sometimes applicants are referring to the polymers by the monomers used to make them or the amounts of the monomers used to make them. While such a description may not include the specific nomenclature used to describe the final polymer or may not contain product-by-process terminology, any such reference to monomers and amounts should be interpreted to mean that the polymer is made from those monomers or that amount of the monomers, and the corresponding polymers and compositions thereof.

The materials, methods, and examples herein are illustrative only and, except as specifically stated, are not intended to be limiting.

The polyolefin compositions and methods described herein may be used to provide long lifetime, highly abrasion-resistant pipes for a wide variety of mining and other transportation uses in a wide range of environmental conditions. High burst strength may be another attribute of the pipes.

Polyolefin Layer Composition

By thermoplastic polyolefin polymer, polyolefin and similar terms used herein, reference is made to a thermoplastic polyolefin comprising copolymerized units of ethylene and an α-olefin having 3 to 20 carbons having a density of about 0.92 g/cc (ASTM D792) or less.

The polyolefin copolymer comprises ethylene and α-olefin comonomers. It comprises at least two monomers, but may incorporate more than two comonomers, such as terpolymers, tetrapolymers and the like. Preferably, the polyolefin copolymer comprises from about 5 wt % to about 50 wt % of the α-olefin comonomer (based on the total weight of the polyolefin copolymer), more preferably about 15 wt % to about 45 wt %, yet more preferably about 20 wt % to about 40 wt %, and most preferably, about 25 wt % to about 35 wt %.

The α-olefin comonomer contains from 3 to 20 carbons and may be a linear, branched or cyclic α-olefin. Preferable α-olefins are selected from the group consisting of propene, 1-butene, 3-methyl-1-butene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 3-cyclohexyl-1-propene, vinyl cyclohexane and the like and mixtures thereof. The α-olefin comonomer preferably contains 3 to 10 carbons. The density of the α-olefin copolymer will generally depend on the type and level of α-olefin incorporated.

The polyolefin copolymer may optionally incorporate a minor amount of other olefinic comonomers; for example cyclic olefins such as norbornene; styrene; dienes such as dicyclopentadiene, ethylidene norbornene and vinyl norbornene; and the like and mixtures thereof. When included, the optional comonomer may be incorporated at a level of about 15 wt % or less, based on the total weight of the polyolefin copolymer.

The polyolefin does not include α,β-ethylenically unsaturated carboxylic acid or anhydride grafted to the parent polyolefin.

The polyolefin may be produced by any known method and may be catalyzed with any known polymerization catalyst such as, for example, radical-, Ziegler-Natta- or metallocene-catalyzed polymerizations (e.g. U.S. Pat. Nos. 3,645,992; 5,026,798; 5,055,438; 5,057,475; 5,064,802; 5,096,867; 5,132,380; 5,231,106; 5,272,236; 5,278,272; 5,374,696; 5,420,220; 5,453,410; 5,470,993; 5,703,187; 5,986,028; 6,013,819; 6,159,608; and EP514828).

Preferably, the polyolefin has a density of about 0.90 g/cc or less, more preferably a density of about 0.88 g/cc or less, and most preferably a density of about 0.88 to about 0.84 g/cc. Blends of two or more polyolefin copolymers may be used, if desired, as long as the density of the blend meets the requirements listed above for the single polyolefin copolymer.

The polyolefin may have Shore A hardness of about 96 or less (ASTM D2240, ISO 868). Preferably, the polyolefin has Shore A hardness of about 80 or less; more preferably, about 70 or less; most preferably, about 70 to about 50. The polyolefin may be blended with other polymeric materials as long as the Shore A hardness of the blend conforms to the above requirements.

The compositions may be used with additives known in the art. The additives include plasticizers, processing aids, flow enhancing additives, flow reducing additives, lubricants, flame retardants, impact modifiers, nucleating agents to increase crystallinity, antiblocking agents such as silica, thermal stabilizers, UV absorbers, UV stabilizers, dispersants, surfactants, chelating agents, coupling agents, adhesives, primers and the like. One of ordinary skill in the art will recognize that additives may be added to the polyolefin composition using techniques known in the art or variants thereof, and will know the proper amounts for addition based upon typical usage. The total amount of additives used in the polyolefin composition may be up to about 15 weight % (based upon the weight of the polyolefin composition).

The polyolefin compositions may contain additives that effectively reduce the melt flow of the resin, which may be present in any amount that permits production of thermoset compositions. The use of such additives will enhance the upper end-use temperature and reduce creep of the pipes produced therefrom. The cured polyolefin compositions may have enhanced resistance to the low molecular weight aromatic fraction and naptha commonly contained in oil sand slurries.

Melt flow reducing additives include organic peroxides, such as 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane-3, di-tert-butyl peroxide, tert-butylcumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, dicumyl peroxide, α,α′-bis (tert-butyl-peroxyisopropyl)benzene, n-butyl-4,4-bis(tert-butylperoxy)valerate, 2,2-bis(tert-butylperoxy)butane, 1,1-bis(tert-butyl-peroxy)cyclohexane, 1,1-bis(tert-butylperoxy)-3,3,5-trimethyl-cyclohexane, tert-butyl peroxybenzoate, benzoyl peroxide, and the like and mixtures combinations thereof. Preferably the organic peroxides decompose at a temperature of about 100° C. or higher to generate radicals. More preferably, the organic peroxides have a decomposition temperature that affords a half life of 10 hours at about 70° C. or higher to provide improved stability for blending operations. The organic peroxides may be added at a level of about 0.01 to about 10 wt %, or about 0.5 to about 3 wt %, based on the total weight of the grafted polyolefin composition.

If desired, initiators such as dibutyltin dilaurate may also be present in the polyolefin composition at about 0.01 to about 0.05 wt %, based on the total weight of the polyolefin composition. Also if desired, inhibitors such as hydroquinone, hydroquinone monomethyl ether, p-benzoquinone, and methylhydroquinone may be added for the purpose of enhancing control to the reaction and stability. The inhibitors may be added at a level of less than about 5 wt %, based on the total weight of the composition.

Alternative melt flow reducing additives include known peroxide-silanol additives that often include a peroxide (as described above), a silane and a catalyst. These additive systems provide moisture curable materials. Such systems may be added in a concentrate form, such as commercially available under the SILCAT trademark (Momentive Performance Materials, Wilton, Conn., USA).

The polyolefin composition may further comprise about 0.1 to about 80 weight % filler based on the total weight of the filled composition.

Preferably, the filler is abrasion-resistant filler. The filler may be reinforcing filler or non-reinforcing filler. Specific examples of preferred reinforcing fillers include high strength fibers such as fiberglass, continuous glass fiber, polyaramide fiber, KEVLAR (a product of E. I. du Pont de Nemours and Company (DuPont), Wilmington, Del.), graphite, carbon fiber, silica, quartz, ceramic, silicon carbide, boron, alumina, alumina-silica, polyethylene, ultrahigh molecular weight polyethylene, polyimide, liquid crystal polymers, polypropylene, polyester, polyamide and the like. For example, US2006/0124188 and US2006/0151042 disclose fiber-reinforced pipe liners. Specific examples of non-reinforcing fillers include particles of abrasion-resistant minerals, marble, slate, granite, sand, potters' sand, silicates, limestone, clay, glass, quartz, metallic powders, aluminum powders, stainless steel powders, zinc metal, refractory metal borides (such as borides of aluminum, niobium, silicon, tantalum, titanium, tungsten, and zirconium), carbides (such as carbides of boron, niobium, silicon, tantalum, titanium, tungsten and zirconium), nitrides (such as nitrides of aluminum, boron, niobium, silicon, tantalum, titanium, tungsten and zirconium), oxides (such as oxides of aluminum, niobium, silicon, tantalum, titanium, tungsten and zirconium), silicon carbide, alumina, fused combinations of alumina and zirconia, calcium carbonate, barium sulfate, magnesium silicate and the like and combinations thereof.

The size of the filler incorporated in the polyolefin composition depends on the thickness and diameter of the polyolefin pipe and should be smaller than the thickness of the polyolefin pipe. Preferably, a mixture of particle sizes is used to provide a higher density (percentage by volume) of filler incorporated. For abrasion-resistant fillers, this may result in a higher abrasion resistance of the filled polyolefin pipe. Filled polymeric pipes are known (U.S. Pat. Nos. 3,498,827; 4,042,559; 4,254,165; 4,407,893; 5,091,260; 5,562,989; and GB 2028461).

Polyolefin Pipe

The article in the form of a pipe comprising the polyolefin composition comprises an innermost layer having a thickness of about 0.001 to about 102 mm (about 0.00004 to about 4 inches) of the polyolefin composition. The pipe may have a hollow circular profile and the wall thickness may be generally uniform around the circumference of the pipe. This should not be taken as limiting. The pipe may have any profile and the wall thickness may vary around the circumference of the pipe as desired. The polyolefin composition is positioned as the innermost layer to provide superior abrasion-resistance. The polyolefin pipe thickness provides not only a long lifetime under extreme abrasive end-use conditions, but also provides desirable high burst strength under the high temperature conditions contemplated herein. Preferably, the polyolefin layer has a thickness of about 3.2 to about 102 mm (about 0.125 to about 4 inches), or about 6.3 to about 76 mm (about 0.25 to about 3 inches), or about 13 to about 51 mm (about 0.5 to about 2 inches) to provide greater levels of end-use lifetime, burst strength and temperature resistance.

The polyolefin pipe may have any dimensions (including outside diameter, inside diameter and length) required to meet the end-use needs. For example but not limitation, the polyolefin pipe preferably has an outer diameter (OD) of about 2.54 to about 254 cm (about 1 to about 100 inches), more preferably, about 25.4 to about 152 cm (about 10 to about 60 inches) and most preferably, about 51 to about 102 cm (about 20 to about 40 inches). For example but not limitation the polyolefin pipe preferably has a length of about 1.5 to about 12.2 m (about 5 to about 40 feet), more preferably about 3.1 to about 9.1 m (about 10 to about 30 feet) and most preferably about 5.5 to about 6.7 m (about 18 to 22 feet), providing a convenient length for storage, transport, handling and installation.

The polyolefin pipe may be produced by any suitable process. For example, the polyolefin pipe may be formed by melt extrusion, melt coextrusion, slush molding, rotomolding, rotational molding or any other procedures known in the art. For example, the polyolefin pipe may be produced by rotational or slush molding processes. The polyolefin composition may be in the form of powder, microbeads or pellets for use in rotational molding processes. Methods for rotational molding of pipes are known (U.S. Pat. Nos. 4,115,508; 4,668,461; and ZA9607413). For example, ZA9607413 discloses wear-resistant composite pipe linings produced through rotational molding a mixture of a polymeric material with an abrasion-resistant particulate material. Methods for rotational molding with polymer powders are known (U.S. Pat. Nos. 3,784,668; 3,876,613; 3,891,597; 3,974,114; 4,029,729; 4,877,562; 5,366,675; 5,367,025; and 5,759,472). U.S. Pat. No. 3,974,114 discloses rotational molding of articles with poly(ethylene-co-acrylic acid) copolymer powders. Methods for rotational molding with polymer microbeads are known (U.S. Pat. No. 5,886,068; EP1422059; and EP1736502). U.S. Pat. No. 5,886,068 discloses rotational molding processes using blends of micropellets. Methods for rotational molding with polymer pellets are known (U.S. Pat. Nos. 4,032,600; 4,185,067; 5,232,644; and EP0778088). Methods for slush molding with polymer powders are known (U.S. Pat. No. 6,218,474 and EP1169390).

Preferably, the polyolefin pipes are formed by melt extrusion and coextrusion processes that are particularly preferred processes for formation of “endless” products. Methods for extruding polymers in the form of pipe are known (U.S. Pat. Nos. 2,502,638; 3,538,209; 3,561,493; 3,755,168; 3,871,807; 3,907,961; 3,936,417; 4,069,001; 4,123,487; 4,125,585; 4,196,464; 4,203,880; 4,301,060; 4,377,545; 4,402,658; 4,465,449; 4,663,107; 4,888,148; 5,028,376; 5,089,204; 5,514,312; 5,518,036; 5,643,526; 5,842,505; 5,976,298; 6,174,981; 6,241,840; 6,418,732; 6,469,079; 6,787,207; US20050167892; US20070117932; EP0222199; EP1574772; WO95/07428; WO2000/018562; WO2006/090016; and WO2006/134228). The molten polymer is forced through an annular die and a mandrel to provide the hollow circular profile of the pipe with the inner pipe diameter controlled by the size of the mandrel. The diameter of the pipe may also be controlled through the application of air pressure inside the pipe. The outer diameter may be controlled with external sizing dies or sleeves. The pipe is cooled to form the final shape. Multilayer pipe is produced similarly using a multilayer annular die that is fed by two or more extruders.

Multilayer Polyolefin Pipe.

The article may be in the form of a multilayer pipe comprising an innermost layer of the polyolefin composition and an outside layer comprising a polymeric material. Examples of preferred polymeric materials for the outside layer include poly(meth)acrylics, polyacrylates, urethane modified polyacrylics, polyester modified polyacrylics, polystyrenes, polyolefins, polyethylenes (such as high density polyethylene, low density polyethylene, linear low density polyethylene, ultralow density polyethylene), polypropylenes, polyurethanes, polyureas, epoxy resins, polyesters (such as poly(ethylene terephthalate), poly(1,3-propyl terephthalate), poly(1,4-butylene terephthalate), PETG, poly(ethylene-co-1,4-cyclohexanedimethanol terephthalate)), alkyd resins, polyamides (such as nylons, nylon 6, nylon 46, nylon 66, nylon 612), polyamideimides, polyvinyls, phenoxy resins, amino resins, melamines, chlorine-containing resins, chlorinated polyethers, fluorine-containing resins, polyvinyl acetals, polyvinyl formals, poly(vinyl butyrate)s, polyacetylenes, polyethers, silicone resins, ABS resins, polysulfones, polyamine sulfones, polyether sulfones, polyphenylene sulfones, polyvinyl chlorides, polyvinylidene chlorides, polyvinyl acetates, polyvinyl alcohols, polyvinyl carbazoles, butyrals, polyphenylene oxides, polypyrroles, polyparaphenylenes, ultraviolet-curing resins, cellulose derivatives, diethylene glycol bis-allyl carbonate poly-4-methylpentene, polytetrafluoroethylene, polytrifluoroethylene, polyvinylidene fluoride, poly(ethylene-co-glycidylmethacrylate), poly(ethylene-co-methyl (meth)acrylate-co-glycidyl acrylate), poly(ethylene-co-n-butyl acrylate-co-glycidyl acrylate), poly(ethylene-co-methyl acrylate), poly(ethylene-co-ethyl acrylate), poly(ethylene-co-butyl acrylate), acid copolymers, acid terpolymers, poly(ethylene-co-(meth)acrylic acid), ionomers, ionomer terpolymers, metal salts of poly(ethylene-co-(meth)acrylic acid), poly((meth)acrylates), poly(ethylene-co-carbon monoxide), poly(ethylene-co-vinyl acetate), poly(ethylene-co-vinyl alcohol), polybutylene, poly(cyclic olefins), syndiotactic polystyrene, poly(4-hydroxystyrene), novalacs, poly(cresols), polycarbonates, poly(bisphenol A carbonate), polysulfides, poly(phenylene sulfide), poly(2,6-dimethylphenylene oxide), elastomers, rubbers, thermoplastic elastomers and the like and copolymers thereof and mixtures thereof.

More preferably, the polymeric materials are selected from the group consisting of rubbers, elastomers, thermoplastic elastomers, acid terpolymers, ionomer terpolymers and the like and combinations thereof. Rubbers and elastomers are generally categorized as diene elastomers, saturated elastomers, thermoplastic elastomers and inorganic elastomers. Specific examples of rubbers and elastomers include natural rubber, polyisoprene, butyl rubber (copolymer of isobutylene and isoprene), polybutadiene, styrene butadiene (SBR, copolymer of polystyrene and polybutadiene), nitrile rubber (copolymer of polybutadiene and acrylonitrile, also referred to as “buna N rubbers”), silicone RTV, FKM VITON (DuPont) (copolymer of vinylidene fluoride and hexafluoropropylene), SANTOPRENE (Advanced Elastomer Systems, LP, Akron, Ohio), fluorosilicone rubber, EPM and EPDM rubber (ethylene propylene rubber, a copolymer of polyethylene and polypropylene), polyurethane rubber, polyurea rubber, resilin, polyacrylic rubber (ABR), epichlorohydrin rubber (ECO), polysulfide rubber, chlorosulfonated polyethylene (CSM, HYPALON (DuPont)) and the like. Thermoplastic elastomers are generally categorized as styrenics (S-TPE), copolyesters (COPE), polyurethanes (TPU), polyamides (PEBA), polyolefin blends (TPO), polyolefin alloys (TPV), reactor TPO (R-TPO), polyolefin plastomers (POP), polyolefin elastomers (POE) and the like. Acid terpolymers are made from α-olefins, α,β-ethylenically unsaturated carboxylic acids and preferably about 10 to about 25 wt % other unsaturated comonomers (all as described above).

The polymer material layer may have any thickness. Preferably, the polymer material layer is about 0.1 to about 102 mm (about 0.004 to about 4 inches), or about 1 to about 25.4 mm (about 0.04 to about 1 inch) or about 2.5 to about 12.7 mm (about 0.1 to about 0.5 inch) thick.

Tielayers may be included between any of the layers to enhance the adhesion between the layers. Any material may be used in tielayers, such as anhydride- or acid-grafted materials. The preferred anhydrides and acids are α,β-ethylenically unsaturated carboxylic acid comonomers selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, fumaric acid, monomethyl maleic acid, and mixtures thereof. Most preferred anhydrides and acids are selected from the group consisting of acrylic acid, maleic anhydride and mixtures thereof. Preferably, the materials to be grafted are selected from the preferred polymeric materials recited above.

Fiber-Reinforced Polyolefin Pipe

The article may be in the form of a multilayer pipe comprising an innermost layer having a thickness of about 0.001 to about 102 mm (0.00004 to 4 inches) comprising the polyolefin composition and an outer layer comprising a fiber reinforcement and optionally a thermoset resin.

The article also may be in the form of a multilayer pipe comprising an innermost layer having a thickness of about 0.001 to about 102 mm (0.00004 to 4 inches) comprising the polyolefin composition; an intermediate layer comprising a polymeric material; and an outer layer comprising fiber reinforcement and optionally thermoset resin.

The fiber reinforcement may be a filament, warp yarn, tape, unidirectional sheet, mat, cloth, knitted cloth, paper, non-woven fabric or woven fabric, or mixtures thereof. The fiber preferably comprises a high strength fiber such as fiberglass, continuous glass fiber, polyaramide fiber, aramid fiber, graphite, carbon fiber, silica, quartz, ceramic, silicon carbide, boron, alumina, alumina-silica, polyethylene, ultrahigh molecular weight polyethylene, polyimide, liquid crystal polymers, polypropylene, polyester, polyamide and the like, and is preferably about 3 to about 30 microns thick.

The fiber may be impregnated with a resin (“prepreg”), such as thermoplastic or preferably thermoset resins. Suitable resins for impregnating the fiber layers include polyester, aromatic, aliphatic, cycloaliphatic or anhydride epoxy resins, vinylester, vinyl, acrylic, modified acrylic, urethane, phenolic, polyimide, bismaleimide, polyurea, siloxane-modified resins and the like and combinations thereof.

Fiber-reinforcement of thermoplastic pipe is known (U.S. Pat. Nos. 4,081,302; 4,521,465; 5,629,062; 5,931,198; 6,737,134; 7,018,691; US2006/0151042; and WO2004/068016).

An adhesive may be applied to the polyolefin pipe and multilayer polyolefin pipe prior to the application of the exterior reinforcement layer and/or an adhesive may be applied to the reinforcement layer after its application to the polyolefin pipe and multilayer polyolefin pipe. The exterior surface of the polyolefin pipe and multilayer polyolefin pipe may be heated to enhance the adhesion and/or embedding of the reinforcement layer. Suitable adhesives may include the impregnated resins described above or any adhesive known in the art.

The fiber reinforcement may be applied to the polyolefin pipe and multilayer polyolefin pipe by any method known in the art. For example, the fiber reinforcement may be applied using known filament winding processes through winding the fiber reinforcement onto the polyolefin pipe or multilayer polyolefin pipe or by wrapping the fiber reinforcement around the polyolefin pipe and multilayer polyolefin pipe.

Polyolefin-Lined Metal Pipe

An embodiment is an article in the form of a multilayer pipe comprising an innermost layer having a thickness of about 0.001 to about 102 mm (0.00004 to 4 inches) comprising the polyolefin composition and an outer layer comprising a metal, preferably in the form of a metal pipe.

The monolayer or multilayer polyolefin composition (such as in the form of pipe, film, or sheet) may be attached (adhered) to the metal outer layer or not attached. The polyolefin or multilayer polyolefin compositions may be self-adhered to the metal layer or adhered through the use of an adhesion primer, coating, or layer. As used herein, when the polyolefin composition is said to be “self-adhered” to the metal layer, it is meant that there is no intermediate layer such as a primer or thin adhesive layer between the metal and the polyolefin or multilayer polyolefin composition.

The pipe may comprise an innermost layer comprising the polyolefin composition; an intermediate layer comprising a polymer material (such as those polymeric materials described above); and an outer layer comprising metal.

The pipe may comprise an innermost layer comprising the polyolefin composition; an intermediate layer comprising a polymer material; and an outer layer comprising metal, wherein the polyolefin layer is adhered to the polymer material layer and the polymer material layer is adhered to the metal layer.

The pipe may comprise an innermost layer comprising the polyolefin composition; an intermediate layer comprising a polymer material; and an outer layer comprising metal, wherein the polyolefin layer is self-adhered to the polymer layer and the polymer layer is self-adhered to the metal layer.

The pipe may further comprise an intermediate layer comprising a fiber reinforcement material comprising a high strength fiber and optionally a thermoset resin as described above.

Preferably, the metal pipe comprises carbon steel, steel, stainless steel, cast iron, galvanized steel, aluminum, copper and the like. More preferably the metal pipe comprises carbon steel to provide the physical properties required for the material conveying processes contemplated herein.

The metal pipe may have any dimensions, including thickness, outer diameter, inner diameter and length suitable for the intended use. The pipe may have a hollow, substantially circular profile and the wall thickness may be generally uniform around the circumference of the pipe, or the pipe may have any profile and the wall thickness may vary around the circumference of the pipe as desired. For example but not limitation, the metal pipe may have a thickness of about 6.3 to about 51 mm (about 0.25 to about 2 inches, about 9.5 to about 38 mm (about 0.375 to about 1.5 inches) or about 13 to about 25.4 mm (about 0.5 to about 1 inch). For example but not limitation, the metal pipe may have an outer diameter (OD) of about 5.1 to about 254 cm (about 2 to about 100 inches), about 25.4 to about 152 cm (about 10 to about 60 inches) or about 51 to about 102 cm (about 20 to about 40 inches). For example but not limitation the metal pipe may have a length of about 1.5 to about 12.2 m (about 5 to about 40 feet), about 3.1 to about 9.1 m (about 10 to about 30 feet) or about 5.5 to about 6.7 m (about 18 to 22 feet) to provide a convenient length for storage, transport, handling and installation.

The polyolefin-lined metal pipe may be produced by any known method. For example, the polyolefin pipe and multilayer polyolefin pipe may serve as a liner for a metal pipe. Methods for lining a pipe with a polymeric liner are known (U.S. Pat. Nos. 3,315,348; 3,429,954; 3,534,465; 3,856,905; 3,959,424; 4,207,130; 4,394,202; 4,863,365; 4,985,196; 4,998,871; 5,072,622; 5,320,388; 5,374,174; 5,395,472; 5,551,484; 5,810,053; 5,861,116; 6,058,978; 6,067,844; 6,240,612; 6,723,266; 2006/0093436; 2006/0108016; US2006/0124188; US2006/0151042; and EP0848659).

The inside surface of the metal pipe may be pretreated to provide enhanced adhesion and stability. Such treatments include descaling by sand-, metal grit- or shot-blasting, acid etching, cleaning the metal surface through solvent or chemical washes to remove grease and/or oxide layers, and the application of adhesion primers, coatings, or layers.

A polyolefin-lined metal pipe may be prepared by pulling or inserting a preformed polyolefin pipe or multilayer polyolefin pipe into a preformed metal pipe wherein the outer diameter of the polyolefin pipe is less than the interior diameter of the metal pipe. This method to produce a polyolefin-lined metal pipe includes the following embodiments.

The method comprises (i) pulling or inserting a pre-formed polyolefin pipe or multilayer polyolefin pipe into the metal pipe; (ii) heating the polyolefin-lined metal pipe above the softening point of the polyolefin composition; and (iii) allowing the metal pipe to cool.

The method comprises (i) heating a metal pipe above the softening point of the polyolefin composition; (ii) pulling or inserting a pre-formed polyolefin pipe or multilayer polyolefin pipe into the heated metal pipe; and (iii) allowing the metal pipe to cool.

The method comprises (i) coating a layer of an adhesive or adhesion primer onto the outside surface of the polyolefin pipe or multilayer polyolefin pipe; and (ii) pulling or inserting the adhesive-treated polyolefin pipe or multilayer polyolefin pipe into the metal pipe.

The method comprises (i) coating a layer of an adhesive or adhesion primer onto the inside surface of the metal pipe; and (ii) pulling or inserting the polyolefin pipe or multilayer polyolefin pipe into the adhesive-treated metal pipe.

The method comprises (i) coating a layer of an adhesive or adhesion primer onto the outside surface of the polyolefin pipe or multilayer polyolefin pipe; (ii) pulling or inserting the adhesive-treated polyolefin pipe or multilayer polyolefin pipe into the metal pipe; (ii) heating the metal pipe above the softening point of the polyolefin composition; and (iv) allowing the metal pipe to cool.

The method comprises (i) coating a layer of an adhesive or adhesion primer onto the inside surface of the metal pipe; (ii) pulling or inserting the polyolefin pipe or multilayer polyolefin pipe into the adhesive-treated metal pipe; (ii) heating the metal pipe above the softening point of the polyolefin composition; and (iv) allowing the metal pipe to cool.

The method comprises (i) coating a layer of an adhesive or adhesion primer onto the outside surface of the polyolefin pipe or multilayer polyolefin pipe; (ii) heating a metal pipe above the softening point of the polyolefin composition; (iii) pulling or inserting the adhesive-treated polyolefin pipe or multilayer polyolefin pipe into the heated metal pipe; and (iv) allowing the metal pipe to cool.

The method comprises (i) coating a layer of an adhesive or adhesion primer onto the inside surface of the metal pipe; (ii) heating the adhesively-treated metal pipe above the softening point of the polyolefin composition; (iii) pulling or inserting the polyolefin pipe or multilayer polyolefin pipe into the heated metal pipe; and (iv) allowing the metal pipe to cool.

In a specific embodiment, the method for adhering the polyolefin pipe or multilayer polyolefin pipe to the metal pipe comprises (a) descaling and cleaning the interior surface of the metal pipe; (b) heating the metal pipe to a temperature of about 150 to about 400° C., preferably about 150 to about 300° C. and most preferably about 175 to about 225° C.; (c) pulling or inserting the polyolefin liner (pipe) or polyolefin multilayer liner (pipe) into the hot metal pipe; and (d) allowing the polyolefin-lined metal pipe to cool to ambient conditions.

For example, preparing a polyolefin lined metal pipe with a self-adhered polyolefin liner (pipe) includes descaling the interior of the metal pipe, followed by degreasing and cleaning The metal pipe is then heated, as in an oven, a furnace, a gas ring burner, electrical resistive heating elements, radiant heaters, induction heating, high frequency electrical heaters and the like, and the heating may be discontinued throughout the remainder of the process or the metal pipe may be continuously heated, as through induction heating, throughout the process. The heating expands the metal pipe. A polyolefin liner (pipe) or polyolefin multilayer liner (pipe) is pulled or inserted into the hot metal pipe. The polyolefin or multilayer polyolefin liner preferably has an outside diameter (OD) that is no greater than about 0.1 inch (2.5 mm) less than the inside diameter (ID) of the unheated metal pipe, more preferably an OD no greater than about 0.05 inch (1.3 mm) less than the ID, even more preferably, an OD no greater than about 0.025 inch (0.64 mm) less than the ID. Most preferably, the polyolefin and multilayer polyolefin liner OD is about equivalent to the ID of the unheated metal pipe. As the heated metal pipe-polyolefin liner structure cools, the metal pipe reduces in diameter and makes intimate contact with the outside surface of the polyolefin liner, causing it to soften and self-adhere to the inside surface of the metal pipe. Alternatively, the polyolefin liner (pipe) or multilayer polyolefin liner (pipe) may be inserted into the metal pipe prior to heating.

If desired, prior to heating the metal pipe and inserting the polyolefin or multilayer polyolefin liner (pipe), an adhesive primer, coating or layer may be applied to the interior surface of the metal pipe, the exterior surface of the polyolefin or multilayer polyolefin liner, or both, in the form of a solution or solid to provide enhanced interlayer adhesion.

A method to produce a polyolefin-lined metal pipe comprises laying up a pre-formed polyolefin film or sheet or multilayer polyolefin film or sheet into a preformed metal pipe. This method to produce a polyolefin-lined metal pipe includes the following embodiments.

The method comprises (i) laying up the interior of a metal pipe with polyolefin film or sheet or multilayer polyolefin film or sheet; (ii) heating a metal pipe above the softening point of the polyolefin composition; and (iii) allowing the metal pipe to cool.

The method comprises (i) coating a layer of an adhesive or adhesion primer onto the outside surface of the polyolefin film or sheet or multilayer polyolefin film or sheet; and (ii) laying up the interior of a metal pipe with polyolefin film or sheet or multilayer polyolefin film or sheet.

The method comprises (i) coating a layer of an adhesive or adhesion primer onto the inside surface of the metal pipe; and (ii) laying up the interior of a metal pipe with polyolefin film or sheet or multilayer polyolefin film or sheet.

The method comprises (i) coating a layer of an adhesive or adhesion primer onto the outside surface of the polyolefin film or sheet or multilayer polyolefin film or sheet; (ii) laying up the interior of a metal pipe with polyolefin film or sheet or multilayer polyolefin film or sheet; (iii) heating a metal pipe above the softening point of the polyolefin composition; and (iv) allowing the metal pipe to cool.

The polyolefin film or sheet and the multilayer polyolefin film or sheet may be produced by any art method. Preferably the film or sheet is produced through melt processes, such as extrusion blown film processes, extrusion film or sheet melt casting processes, sheet profile extrusion processes, calendar processes and the like. The films and sheets may undergo secondary formation processes, such as the plying together of preformed sheets to produce thicker sheets through known calendaring processes.

An example method for preparing polyolefin lined metal pipe with a self-adhered polyolefin sheet includes descaling the interior of the metal pipe, followed by degreasing and cleaning. The interior of the metal pipe is then covered with the polyolefin sheet, preferably with the sheet overlapping onto itself 0.5 to 4 inches to form a seam. The seam may be heat fused or the excess sheet may be trimmed and the sheet ends may be heat fused, as desired. The metal pipe is then heated, as described above, to the temperature range of about 150 to about 400° C., preferably to the temperature range of about 150 to about 300° C. and most preferably to the temperature range of about 175 to about 225° C. As the heated metal pipe-polyolefin sheet structure cools, the metal pipe makes intimate contact with the outside surface of the polyolefin sheet, causing it to soften and self-adhere to the inside surface of the metal pipe.

If desired, prior to heating the metal pipe and inserting the polyolefin or multilayer polyolefin film or sheet, an adhesive primer, coating or layer may be applied to the interior surface of the metal pipe, the exterior surface of the polyolefin or multilayer polyolefin film or sheet or both, in the form of a solution or solid to provide enhanced interlayer adhesion.

The polyolefin-lined metal pipe may be produced by powder coating processes. Methods for coating the inner or outer surfaces of a pipe with polymeric powder coatings are known (U.S. Pat. Nos. 3,004,861; 3,016,875; 3,063,860; 3,074,808; 3,138,483; 3,186,860; 3,207,618; 3,230,105; 3,245,824; 3,307,996; 3,488,206; 3,532,531; 3,974,306; 3,982,050; 4,007,298; 4,481,239; and EP778088). For example, U.S. Pat. No. 4,407,893 discloses powder coating processes to produce abrasion-resistant pipes with 0.04-inch thick coatings of sand-filled blends comprising polyethylenes and ionomers.

The polyolefin composition may be produced in the form of a powder by any known method. Methods for producing polymer powders (comprising acid copolymers and ionomers), and powder coating compositions are known (U.S. Pat. Nos. 3,933,954; 3,959,539; 4,056,653; 4,237,037; 5,344,883; 6,107,412; 6,132,883; 6,284,311; 6,544,596; 6,680,082; and EP1169390).

Preferably, the polyolefin composition is cryogenically (for example, with liquid nitrogen as the cooling medium) ground into a powder. Physically grinding the grafted polyolefin composition creates irregularly shaped particles of size and shape suitable for achieving constant flow through the application equipment. Preferably, the grafted polyolefin composition powder has a particle size or average particle size of about 20 to about 500 micrometers. To obtain the suitable particle size, the grinding step may include a sieving or classification step to eliminate large- and fine-sized particles. For fluid bed coating processes, the preferred particle size is of about 75 to about 350 micrometers.

A method to produce a polyolefin-lined metal pipe comprises (i) heating a metal pipe above the softening point of a polyolefin composition; (ii) fluidizing the polyolefin composition in the form of a powder; (iii) supplying the fluidized polyolefin powder to the inside of the heated metal pipe until the desired polyolefin thickness is achieved; and (iv) allowing the metal pipe to cool.

The heated metal pipe may be in a vertical orientation or a horizontal orientation during step (iii). The heated metal pipe may be rotated during step (iii). For example, the heated metal pipe may be rotated at a rate to force the polyolefin powder to the inside diameter of the metal pipe during step (iii).

The powder coating process comprises heating the metal pipe to a temperature above the softening point of the polyolefin composition and supplying a fluidized powder of the polyolefin composition into the heated pipe for a time sufficient to provide the desired polyolefin coating thickness. The metal pipe is preferably heated to the temperature range of about 150 to about 400° C., preferably about 200 to about 350° C. and most preferably about 250 to about 300° C. The metal pipe may be heated as described above and the heating may be discontinued throughout the remainder of the process or the metal pipe may be continuously heated throughout the process. Portions of the pipe may be selectively heated. For example, in a fluidized bed method (see below) the metal pipe may be incrementally heated from the top to the bottom to cause the coating to form sequentially from the top to the bottom. Conversely, the metal pipe may be heated from the bottom to the top.

The polyolefin coating may be self-adhered to the metal pipe or the interior surface of the metal pipe may be treated with adhesion primers, coatings and layers. The use of adhesion promoting primers and coupling agents for pipe powder coatings is known (U.S. Pat. Nos. 3,016,875; 4,048,355; and 4,481,239).

Pipe powder coating methods may include descaling, degreasing and cleaning the interior of the metal pipe, as described above. The portions of the pipe that are not desired to be coated, for example the metal pipe ends which are meant to be joined together to form the pipeline, may be masked. If desired, prior to feeding the powder, an adhesive primer, coating or layer may be applied to the interior surface of the metal pipe in the form of a solution or solid (powder) to provide enhanced interlayer adhesion. The metal pipe is then heated as described above. The metal pipe temperature may be varied as desired during the coating operation. Preferably, the heated metal pipe may be rotated about its cylindrical axis at a rate of about 1 to about 300 rpm, more preferably about 10 to about 80 rpm. The metal pipe may be rotated slowly to provide good, even coverage of the powder coating or may be rotated fast enough to force the powder to the interior surface of the pipe. The metal pipe may be in a vertical orientation or preferably in a horizontal orientation. If a multilayer coating is desired, different polymeric composition powders may be fed sequentially to provide the different coating layers at the thickness desired. At any stage of the process, abrasion-resistant particles, such as described above as fillers, may be fed into the interior of the metal pipe, either individually or in combination with the powder. For example, the abrasion-resistant particles may be overcoated onto the hot coating while it is still soft and tacky so that the particles adhere to the interior surface of the coating. The coated metal pipe is then allowed to cool to ambient temperatures. If desired, any coating surface roughness may be smoothed through a post-coating operation, such as by hot gas, flame or oven post-treatments.

In a fluidized bed method, the powder is fed with pressurized gas, such as compressed air, nitrogen or argon, from a fluidized bed of the powder into the interior of the hot metal pipe. Alternatively, the hot metal pipe may be placed above the fluidized bed and the fluidized bed allowed to expand into the interior of the hot metal pipe to be coated. As the powder contacts the heated interior surface of the metal pipe, the material coalesces and flows to form a continuous, fused coating. The powder is fed from the fluidized bed until a continuous, uniform coating of the desired thickness is achieved.

In a spray coating method, a spray nozzle, preferably with a deflector disc to force the powder radially out onto the metal pipe interior surface, supported on an extensible boom, is inserted down the centerline of the metal pipe interior. The powder may be fed with pressurized gas, such as compressed air, nitrogen or argon, from a fluidized bed of the powder. Alternatively, the powder may be delivered from a bin to a vibrating feeder into a hopper and then conveyed to the spray nozzle with a pressurized gas. During the coating operation, the spray nozzle, the metal pipe or both may be moved to ensure uniform coating over the interior surface of the pipe. Multiple coats may be applied to provide the desired coating thicknesses.

The polyolefin composition powder may be applied to the inside metal pipe surface through electrostatic spraying processes. For electrostatic spraying applications, the preferred particle size is about 20 to about 120 micrometers. Preferably, the metal pipe is preheated above the softening point of the polyolefin composition as described above. In electrostatic spraying processes, the polyolefin powder is fed out of a reservoir, such as a fluidized bed, to a spray gun by air pressure. A high voltage, low amperage electrostatic charge is applied to the polyolefin powder by a transfer of electrons from the spray gun to the powder. The charged powder is sprayed onto the cleaned inside surface of the preheated, grounded metal pipe to form the polyolefin coating. Several passes may be required to build up to the desired thickness of the coating.

The polyolefin composition coating may be applied to the metal pipe by thermal spraying processes, such as flame (combustion) spraying, two wire arc spraying, plasma spraying, cold spraying and high velocity oxy-fuel spraying. Preferably, the thermal spraying process is a flame spraying process. The polyolefin composition may be in the form of a wire or a rod to serve as a feedstock for flame spraying processes, or it is a powder with a preferred particle size of about 1 to about 50 micrometers. The polyolefin powder is fed to the flame spraying gun in a stream of an inert gas (such as argon or nitrogen) and fed into a flame of a fuel gas (such as acetylene or propane) and oxygen. The polyolefin powder is melted in the flame and is sprayed onto the cleaned inside surface of the preheated metal pipe with the help of a second outer annular gas nozzle of compressed air to form the polyolefin coating. Several passes may be required to build up to the desired thickness of the polyolefin coating. Alternatively, the polyolefin powder may be fed to the flame spray gun using a venturi effect sustained by the fuel gas flow.

The polyolefin compositions may be too soft for the formation of suitable powder to support powder-based processes. Even if suitable powder were produced from the polyolefin compositions, the powder may tend to mass (stick together). Powder-based processes to produce the pipe are therefore not preferred.

The polyolefin-lined metal pipe may be produced by processes similar to the above mentioned rotational or slush molding processes. The polyolefin composition may be in the form of powder, microbeads or pellets. The coating process comprises heating the metal pipe to a temperature above the softening point of the polyolefin composition, horizontally rotating the pipe and supplying the polyolefin composition into the heated pipe for a time sufficient to provide the desired polyolefin coating thickness. The metal pipe may be preheated (such as in an oven), may be constantly heated during the process or both. The polyolefin composition may be fed all at once (batchwise) or continuously to the rotating heated metal pipe. After an even coating of the desired thickness of the polyolefin composition is applied to the inner surface of the metal pipe, the pipe is cooled.

The pipes described herein provide high abrasion-resistance and corrosion resistance for the conveyance of solids and slurries such as found in the agriculture, food and mining industries. The polyolefin layer in the pipes provides very long lifetime, especially desirable for those industries that require long service lifetime due to the great maintenance and replacement complexity and cost. For example, oil slurry mining operations require kilometers of slurry pipelines in extreme environments, such as northern Alberta, Canada, so extended pipe lifetime is very desirable.

A method for transporting an abrasive material comprises obtaining a pipe- or tube-formed article as described above; preparing an abrasive material composition suitable for flowing through the article; flowing the abrasive material composition into one end of the pipe- or tube-formed article and receiving the abrasive material composition out of the other end of pipe- or tube-formed article. The abrasive material composition may be moved through the pipe by any motive force such as gravity and/or the action of a pump such as a jet pump.

The abrasive material composition may be a slurry, such as a combination of water, oil, air, emulsified materials, particulates, solids and/or the like. A slurry of note is oil sand slurry. In some cases, the abrasive material, such as oil sand slurry, may be at a temperature of about 30° C. or greater, of about 40° C. or greater, or about 50° C. or greater. Oil sand slurries may be prepared as described in, for example, US2006/0249431. The oil sand slurry may be optionally conditioned by transport through the pipe- or tube-formed article, such conditioning comprising for example lump digestion, bitumen liberation, coalescence and/or aeration. Pumping the slurry through a pipeline over a certain minimum distance (such as at least one kilometer, preferably at least 2 kilometers), allows for conditioning the slurry. This is due to the increased time (such as 10 minutes or greater) in the pipeline, which allows transport through the pipeline to replace conditioning of the oil sand in a batch tumbler. In a low energy extraction process, the mined oil sand is mixed with water in predetermined proportions near the mine site to produce a slurry containing entrained air with density of 1.4 to 1.65 g/cc and preferably a temperature of 20-40° C. Pumping the slurry through a pipeline having a plurality of pumps spaced along its length, preferably adding air to the slurry as it moves through the pipeline, conditions the slurry for further operations to extract bitumen from the slurry.

EXAMPLES

The following Examples are intended to be illustrative of the invention, and are not intended in any way to limit its scope.

Methods

Melt Index (MI) was measured by ASTM D1238 at 190° C. using a 2160 g, unless indicated otherwise. A similar ISO test is ISO 1133. Shore A hardness is measured according to ASTM D2240, ISO 868.

Materials Used

-   PO1: high density polyethylene (density 0.960 g/cc) with MI of 2     g/10 min. -   PO2: poly(ethylene-co-hexene) (density 0.918 g/cc) with MI of 2 g/10     min. -   PO3: poly(ethylene-co-hexene) (density 0.918 g/cc) with MI of 2.7     g/10 min. -   PO4: an EPDM (density of 0.882 g/cc) with MI of 23 g/10 min. -   PO5: poly(ethylene-co-butene) (density 0.873 g/cc) with MI of 3.7     g/10 min. -   PO6: poly(ethylene-co-octene) (density 0.863 g/cc) with MI of 1.6     g/10 min. -   ACR: poly(ethylene-co-n-butylacrylate-co-methacrylic acid)     containing 23 wt % n-butylacrylate and 9 wt % methacrylic acid with     MI of 5 g/10 min. -   EO: ametallocene-catalyzed ethylene-octene copolymer plastomer sold     as EXACT 5361 by ExxonMobil Chemical Company, Houston, Tex.     (ExxonMobil). -   EP1: a metallocene-catalyzed ethylene-propylene copolymer, sold as     VISTALON EPM 722 by ExxonMobil. -   EP2: a metallocene-catalyzed ethylene-propylene copolymer, sold as     VISTAMAXX VM1100 by ExxonMobil. -   EP3: EP2 grafted with 2 wt % maleic anhydride. -   EPDM: a metallocene-catalyzed ethylene-propylene-diene copolymer,     sold as VISTALON 5601 by ExxonMobil. -   HDPE1: a high density poly(ethylene). -   HDPE2: a high density poly(ethylene) grafted with 1.5 wt % maleic     anhydride. -   S: a styrene block copolymer sold as KRATON G7705-1 by Kraton     Polymers, Houston, Tex. (Kraton). -   SBS: a styrene-butadiene-styrene block copolymer with MI of 3 g/10     min at 200° C./5 kg, sold as KRATON D1153E (Kraton). -   SEBS 1: a styrene-ethylene/styrene block copolymer with MI of 5 g/10     min at 230° C./5 kg, sold as KRATON G1652M (Kraton). -   SEBS 2: a styrene-ethylene/styrene block copolymer grafted with 1.7     wt % maleic anhydride, sold as KRATON FG1901X (Kraton). -   SEBS 3: a styrene-ethylene/styrene block copolymer grafted with 1 wt     % maleic anhydride, sold as KRATON FG1924X (Kraton). -   SIS: a styrene-isoprene-styrene block copolymer with MI of 3 g/10     min at 200° C./5 kg, sold as KRATON D111K (Kraton).

Comparative Example CE 1 and Examples 1-7

Abrasion resistance is assessed according to the following procedure. Wear test coupons are cut from injection molded plaques of the low density polyolefins PO2 to PO6 and for comparison, high density PO1. The wear test coupons are 50 mm by 50 mm by 6.35 mm thick. The wear test coupons are dried in a vacuum oven (20 inches Hg) at a temperature of 35° C. until the weight loss is less than 1 mg/day and then weighed. The wear test coupons are then mounted in a test chamber and a 10 wt % aqueous sand (AFS50-70 test sand) slurry at room temperature (20-25° C.) is impinged on the wear test coupon through a slurry jet nozzle positioned 100 mm from its surface with a diameter of 4 mm at a slurry jet rate of 15-16 meters/second with a slurry jet angle of 90° relative to the surface plane for 2 hours. Example 6 is performed with the 10 wt % aqueous sand slurry at a temperature of 30° C. Example 7 is performed with the 10 wt % aqueous sand slurry at a temperature of 20° C. The wear test coupons are then removed and dried in a vacuum oven (20 inches Hg) at room temperature for at least 15 hours and then reweighed. The weight loss in grams and % indicates the amount of wear

TABLE 1 Example CE 1 1 2 3 4 5 6 7 Material PO1 PO2 PO3 PO4 PO5 PO6 PO5 PO6

Examples 8-16

The polyolefin pipes summarized in Table 2 are made from the materials listed by conventional pipe extrusion and sizing methods with melt extrusion temperatures of about 150° C. to about 225° C. The pipes are cut into 20 foot lengths. “OD”=outer diameter.

TABLE 2 Monolayer Polyolefin Pipes OD Thickness Example Material (inches) (inches) 8 PO5 20 0.5 9 PO6 24 1.0 10 PO5 28 2.0 11 PO2 22 0.38 12 PO3 26 0.75 13 PO6 32 1.5 14 PO4 26 0.4 15 PO5 30 1.0 16 PO6 34 1.8

Examples 17-22

The polyolefin bilayer pipes summarized in Table 3 are made from the materials in Table 3 by conventional multilayer pipe extrusion and sizing methods with melt extrusion temperatures of about 150° C. to about 225° C. The pipes are cut into 20 foot lengths.

TABLE 3 Inner Layer Outer Layer Thickness Thickness Example Material (inch) Material (inch) OD (in) 17 PO5 0.5 ACR 0.25 20 18 PO3 1.0 EPDM 0.4 24 19 PO5 2.0 HDPE 1 0.5 28 20 PO6 0.38 SEBS 2 0.2 22 21 PO4 0.75 SEBS 3 0.3 26 22 PO6 1.5 HDPE 2 0.5 32

Examples 23-31

Multilayer polyolefin pipes are made from the materials summarized in Table 4 by conventional multilayer pipe extrusion and sizing methods with melt extrusion temperatures of about 150° C. to about 225° C. The tielayer is approximately 1-2 mils thick (0.026-0.051 mm) and is positioned between the inner layer and outer layer to provide adhesion. All Examples also have a tielayer on the outside surface of the outer layer, e.g.; the structure of the pipe is tielayer/outer layer/tielayer/inner layer. The pipes are cut into 20-foot lengths.

TABLE 4 Inner Layer Outer Layer Exam- Thickness Tie Layer Thickness ple Material (inch) Material Material (inch) OD (in) 23 PO5 0.5 EP 3 EO 0.25 20 24 PO3 1.0 EP 3 EP 1 0.4 24 25 PO6 2.0 EP 3 EP 2 0.5 28 26 PO4 0.38 EP 3 EPDM 0.2 22 27 PO5 0.75 HDPE 2 HDPE 1 0.3 26 28 PO5 1.5 SEBS 2 S 0.5 32 29 PO6 0.45 SEBS 3 SBS 0.2 26 30 PO6 1.0 SEBS 2 SEBS 1 0.1 30 31 PO4 1.8 SEBS 2 SIS 0.3 34

Examples 32-38

The polyolefin pipe-lined carbon steel pipes summarized in Table 5 are made by inserting the polyolefin pipes listed into 20-foot lengths of carbon steel pipes with 0.75-inch wall thickness with the inner diameter (ID) listed. Prior to lining the pipe, the interior surface of the carbon steel pipe is sandblasted and degreased.

TABLE 5 Polyolefin Pipe Carbon Steel Pipe Example (Example) ID (inches) 32 8 22 33 12 28 34 15 32 35 18 26 36 22 34 37 26 24 38 29 28

Examples 39-46

The polyolefin pipe-lined pipelines summarized in Table 6 are made by thermally fusing the ends (“butt fusion”) of the polyolefin pipes listed through conventional methods and inserting the polymeric pipes into the carbon steel pipes with 0.75-inch wall thickness and the length and the inner diameter (ID) listed. Prior to lining the pipe, the interior surface of the carbon steel pipe is sandblasted and degreased.

TABLE 6 Polyolefin Pipe Carbon Steel Pipeline Example (Example) ID (inch) Length (km) 39 9 26 1 40 11 24 2 41 16 36 3 42 17 22 0.5 43 19 30 1.5 44 24 26 1 45 39 28 2 46 30 32 3

Examples 47-68

The polyolefin pipe-lined carbon steel pipes summarized in Table 7 are made by heating 20 foot lengths of carbon steel pipes with 0.75-inch wall thickness and the inner diameter (ID) listed to 200° C.; inserting the polyolefin pipes listed into the hot carbon steel pipes; and allowing the lined pipe to cool to ambient temperatures. Prior to lining the pipe, the interior surface of the carbon steel pipe is sandblasted and degreased.

TABLE 7 Polyolefin Pipe Carbon Steel Pipe Example (Example) ID (inches) 47 8 20 48 9 24 49 10 28 50 11 22 51 12 26 52 13 32 53 14 26 54 15 30 55 16 34 56 17 20 57 20 22 58 21 26 59 22 32 60 23 20 61 24 24 62 25 28 63 26 22 64 27 26 65 28 32 66 29 26 67 30 30 68 31 34

Preparative Examples PE1-PE9

Polyolefin sheets with a thickness of 0.125 inch and a width of 9 feet are made from the materials summarized in Table 8 by conventional sheet extrusion methods with melt extrusion temperatures of about 150° C. to about 225° C. The sheets are plied together to provide the described thickness by conventional calendering processes.

TABLE 8 Polyolefin Sheets Preparative Example Material Sheet (inches) PE1 PO5 0.5 PE2 PO5 1.0 PE3 PO5 2.0 PE4 PO6 0.25 PE5 PO3 0.75 PE6 PO4 1.5 PE7 PO6 0.5 PE8 PO6 1.0 PE9 PO6 1.75

Examples 69-77

The polyolefin-lined carbon steel pipes summarized in Table 9 are made by inserting the polyolefin sheets listed into 20-foot lengths of carbon steel pipes with 0.75-inch wall thickness with the inner diameter (ID) listed. Prior to lining the pipe, the interior surface of the carbon steel pipe is sandblasted and degreased. The polyolefin sheets are cut down in size to fit the carbon steel pipe and the seam is butt welded by thermally fusing the ends (“butt fusion”). The polyolefin-lined carbon steel pipe is heated to 200° C. while being rotated in the horizontal axis, and then the lined pipe is cooled to ambient temperatures.

TABLE 9 Polyolefin Sheet Carbon Steel Pipe Example (Example) ID (inches) 69 PE1 22 70 PE2 28 71 PE3 32 72 PE4 26 73 PE5 34 74 PE6 24 75 PE7 28 76 PE8 20 77 PE9 30 

The invention claimed is:
 1. A pipe- or tube-shaped article having an innermost layer wherein the innermost layer has a thickness of about 0.001 to about 102 mm and comprises a polyolefin; the polyolefin comprises repeat units derived from ethylene and 5 to 50 wt %, based on the total weight of the polyolefin, of an α-olefin having 3 to 20 carbons, and has a density of 0.90 g/cc (ASTM D-792) or less; and the innermost layer does not comprise an ionomer or an α,β-ethylenically unsaturated carboxylic acid or anhydride grafted to a parent polyolefin, wherein the article is abrasion-resistant article; the polyolefin has a density of about 0.88 g/cc or less; the α-olefin contains from 3 to 10 carbons; and the α-olefins are selected from the group consisting of propene, 1-butene, 3-methyl-1-butene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 3-cyclohexyl-1-propene, vinyl cyclohexane.
 2. The article of claim 1 wherein the polyolefin has a density of 0.84-0.88 g/cc.
 3. The article of claim 1 wherein the article further comprises an outermost layer in contact with the innermost layer and the outermost layer comprises carbon steel, wherein the innermost layer is self-adhered to the outermost layer.
 4. The article of claim 1 wherein the article comprises an innermost layer comprising the polyolefin; an intermediate layer comprising a polymer material wherein the polymer material comprises an anhydride- or acid-grafted polyethylene, acid copolymer, acid terpolymer, ionomer, ionomer terpolymer, or mixtures of two or more thereof; and an outer layer comprising metal.
 5. The article of claim 1 wherein the article comprises an innermost layer comprising the polyolefin; an intermediate layer comprising a polymer material wherein the polymer material comprises an anhydride- or acid-grafted polyethylene, acid copolymer, acid terpolymer, ionomer, ionomer terpolymer, or mixtures of two or more thereof; and an outer layer comprising metal, wherein the polyolefin layer is adhered to the polymer material layer and the polymer material layer is adhered to the metal layer.
 6. The article of claim 1 wherein the article comprises an innermost layer comprising the polyolefin; an intermediate layer comprising a polymer material wherein the polymer material comprises an anhydride- or acid-grafted polyethylene, acid copolymer, acid terpolymer, ionomer, ionomer terpolymer, or mixtures of two or more thereof; and an outer layer comprising metal, wherein the polyolefin layer is self-adhered to the polymer material layer and the polymer material layer is self-adhered to the metal layer.
 7. The article of claim 1 further comprising an outer layer having a thickness of about 0.1 to about 102 mm and comprising anhydride- or acid-grafted polyethylene, acid copolymer, acid terpolymer, ionomer, ionomer terpolymer, or mixtures of two or more thereof.
 8. The article of claim 7 further comprising a tie layer between the innermost layer and the outer layer and the tie layer comprises an anhydride- or acid-grafted material.
 9. The article of claim 7 further comprising an intermediate layer between the innermost layer and the outer layer and the intermediate layer comprises an anhydride- or acid-grafted polyethylene.
 10. The article of claim 1 further comprising an outermost layer.
 11. The article of claim 10 comprising an outermost layer which comprises carbon steel, steel, stainless steel, cast iron, galvanized steel, aluminum, or copper, or alloys of two or more thereof.
 12. The article of claim 11 wherein the outermost layer comprises carbon steel.
 13. The article of claim 1 further comprising an outermost layer in contact with the innermost layer, wherein the innermost layer is self-adhered to the outermost layer.
 14. The article of claim 13 comprising an outermost layer, in contact with the innermost layer, comprising carbon steel, steel, stainless steel, cast iron, galvanized steel, aluminum, or copper, or alloys of two or more thereof.
 15. The article of claim 14 wherein the innermost layer is in contact with the outermost layer and the outermost layer comprises carbon steel. 